Virus-Induced Gene Silencing (VIGS) in Cassava Using Geminivirus Agroclones.

Virus-induced gene silencing (VIGS) is an efficient, low-cost, and rapid functional validation tool for candidate genes in planta. The VIGS approach is particularly suitable to perform reverse genetics studies in crop species. Here we present a detailed method to perform VIGS in cassava, from target gene fragment to agroinoculation and VIGS quantitation.

Genetic Transformation of Recalcitrant Cassava by Embryo Selection and Increased Hormone Levels.

Genetic engineering is considered to be an important tool for the improvement of cassava. Cassava is a highly heterozygous crop species for which conventional breeding is a lengthy and tedious process. Robust transformation is based on Agrobacterium-mediated transformation of friable embryogenic callus (FEC).

Cassava geminivirus agroclones for virus-induced gene silencing in cassava leaves and roots.

Aim: We report the construction of a Virus-Induced Gene Silencing (VIGS) vector and an agroinoculation protocol for gene silencing in cassava ( Crantz) leaves and roots. The African cassava mosaic virus isolate from Nigeria (ACMV-[NOg]), which was initially cloned in a binary vector for agroinoculation assays, was modified for application as VIGS vector. The functionality of the VIGS vector was validated in and subsequently applied in wild-type and transgenic cassava plants expressing the gene under the control of the CaMV 35S promoter in order to facilitate the visualization of gene silencing in root tissues.

Transformation of Solanum tuberosum plastids allows high expression levels of β-glucuronidase both in leaves and microtubers developed in vitro.

Plastid genome transformation offers an attractive methodology for transgene expression in plants, but for potato, only expression of gfp transgene (besides the selective gene aadA) has been published. We report here successful expression of β-glucuronidase in transplastomic Solanum tuberosum (var. Desiree) plants, with accumulation levels for the recombinant protein of up to 41% of total soluble protein in mature leaves.

High expression level of a foot and mouth disease virus epitope in tobacco transplastomic plants.

Chloroplast transformation has an extraordinary potential for antigen production in plants because of the capacity to accumulate high levels of recombinant proteins and increased biosafety due to maternal plastid inheritance in most crops. In this article, we evaluate tobacco chloroplasts transformation for the production of a highly immunogenic epitope containing amino acid residues 135-160 of the structural protein VP1 of the foot and mouth disease virus (FMDV). To increase the accumulation levels, the peptide was expressed as a fusion protein with the beta-glucuronidase reporter gene (uidA).